extern void ziya(void);
extern char my_var;

void kernel_main(void)
{
    int a = 0;
    ziya();

    char* video = (char*) 0xb8000;
    *video = my_var;
}

void c_test(char a)
{
    char* video = (char*) 0xb8000;
    *(video + 2) = a;
}

